# TPS3851H18SQDRBRQ1

**Texas Instruments** · Supervisor And Reset ICs · SON-8-EP(3x3)

TPS3851H18SQDRBRQ1 from Texas Instruments, in a SON-8-EP(3x3). Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | VDD | power_in | Power supply voltage pin; 1.6V to 6.5V input range; recommended to connect 0.1µF bypass capacitor for noisy systems. |
| 2 | CWD | input | Programmable watchdog timeout input; connect capacitor to GND for user-programmable timeout or 10kΩ pull-up to VDD for factory preset timing. |
| 3 | MR | input | Manual reset input; logic low level triggers RESET; internally pulled up. |
| 4 | GND | power_in | Ground reference pin; thermal pad internally connected to GND. |
| 5 | SET1 | input | Logic input for watchdog enable/disable control; grounding this pin disables the watchdog timer. |
| 6 | WDI | input | Watchdog input; falling edge must occur before watchdog timeout (tWD) expires; must be driven to VDD or GND when unused. |
| 7 | WDO | output | Watchdog output (open-drain); goes low after watchdog timeout; connect with 1kΩ to 100kΩ pull-up resistor to VPU. |
| 8 | RESET | output | Reset output (open-drain); goes low when VDD falls below VITN; connect with 1kΩ to 100kΩ pull-up resistor to VPU; RESET delay time (tRST) = 200ms typical. |
| 9 | Thermal Pad | passive | Exposed pad (from the footprint; not named in the datasheet pin table). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SON-8-EP(3x3) |
| Category | Power Management (PMIC) |
| Pins | 9 |

## CAD (KiCad official)

- Symbol: `TPS3851H18SQDRBRQ1`
- Footprint: `Package_SON:WSON-8-1EP_3x3mm_P0.5mm_EP1.6x2.0mm`
- 3D model: SON-8-EP(3x3) (KiCad packages3D, STEP)
- 3D model files: `tps3851h18sqdrbrq1-etched.step` / `tps3851h18sqdrbrq1-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tps3851h18sqdrbrq1.step` / `tps3851h18sqdrbrq1.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/cn/lit/gpn/tps3851-q1) (39 pp, sha256 `187a2d3c4a847f7d`, retrieved 2026-10-05, tier: lcsc)
- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-4-5-20251001` (text), consensus `claude-sonnet-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/tps3851h18sqdrbrq1-datasheet.pdf)